Currently the liquid crystal compounds are widely applied in various types of displays, electro-optical devices, sensors and the like. A large number of liquid crystal compounds have been used in display area, wherein the nematic liquid crystal is most widely used. Nematic liquid crystals have been used in passive TN, STN matrix display and TFT active matrix system.
Although the technology of thin-film-transistor liquid-crystal display (TFT-LCD) has been mature, it should be continuously improved to decrease the response time, to widen the phase transition temperature, to decrease the driving voltage, and so on. It has been well-known that liquid crystals play an important role to improve the characteristics of LCDs.
The liquid crystal compounds are required to have high chemical and thermal stability, as well as high stability in electric field and electromagnetic radiation. The liquid crystal compounds used in TFT-LCD not only should be stable to heat, UV light, electric field, and electromagnetic radiation, but also have the wide temperature range of a nematic phase, appropriate optical anisotropy, very high resistance, high voltage holding ratio, and good intermiscibility with other liquid crystal compounds.
In order to improve performance of the liquid crystal display, to develop a low rotational viscosity γ1 (even at low temperature), a high dielectric anisotropy (Δ∈) of the liquid crystal mixture has an important significance. Therefore, the development of liquid crystal monomer having appropriate physical and chemical properties is the top priority in the future research.
A liquid crystal compound having a benzene derivatives group that hydrogen substituted by deuterium will have good performance but no technical limitations.